Simplifying Client constructor's for Bigtable and Spanner.

bigtable/google/cloud/bigtable/client.py

@@ -31,16 +31,14 @@
 
 import os
 
-import google.auth
 import google.auth.credentials
 from google.gax.utils import metrics
 from google.longrunning import operations_grpc
 
 from google.cloud._helpers import make_insecure_stub
 from google.cloud._helpers import make_secure_stub
 from google.cloud._http import DEFAULT_USER_AGENT
-from google.cloud.client import _ClientFactoryMixin
-from google.cloud.client import _ClientProjectMixin
+from google.cloud.client import ClientWithProject
 from google.cloud.environment_vars import BIGTABLE_EMULATOR
 
 from google.cloud.bigtable import __version__
@@ -166,13 +164,13 @@ def _make_table_stub(client):
             client.emulator_host)
 
 
-class Client(_ClientFactoryMixin, _ClientProjectMixin):
+class Client(ClientWithProject):
     """Client for interacting with Google Cloud Bigtable API.
 
     .. note::
 
         Since the Cloud Bigtable API requires the gRPC transport, no
-        ``http`` argument is accepted by this class.
+        ``_http`` argument is accepted by this class.
 
     :type project: :class:`str` or :func:`unicode <unicode>`
     :param project: (Optional) The ID of the project which owns the
@@ -209,31 +207,17 @@ class Client(_ClientFactoryMixin, _ClientProjectMixin):
 
     def __init__(self, project=None, credentials=None,
                  read_only=False, admin=False, user_agent=DEFAULT_USER_AGENT):
-        _ClientProjectMixin.__init__(self, project=project)
-        if credentials is None:
-            credentials, _ = google.auth.default()
-
         if read_only and admin:
             raise ValueError('A read-only client cannot also perform'
                              'administrative actions.')
 
-        scopes = []
-        if read_only:
-            scopes.append(READ_ONLY_SCOPE)
-        else:
-            scopes.append(DATA_SCOPE)
-
+        # NOTE: This API has no use for the _http argument, but sending it
+        #       will have no impact since the _http() @property only lazily
+        #       creates a working HTTP object.
+        super(Client, self).__init__(
+            project=project, credentials=credentials, _http=None)
         self._read_only = bool(read_only)
-
-        if admin:
-            scopes.append(ADMIN_SCOPE)
-
         self._admin = bool(admin)
-
-        credentials = google.auth.credentials.with_scopes_if_required(
-            credentials, scopes)
-
-        self._credentials = credentials
         self.user_agent = user_agent
         self.emulator_host = os.getenv(BIGTABLE_EMULATOR)
 
@@ -244,6 +228,22 @@ def __init__(self, project=None, credentials=None,
             self._operations_stub_internal = _make_operations_stub(self)
             self._table_stub_internal = _make_table_stub(self)
 
+        self._set_scopes()
+
+    def _set_scopes(self):
+        """Set the scopes on the current credentials."""
+        scopes = []
+        if self._read_only:
+            scopes.append(READ_ONLY_SCOPE)
+        else:
+            scopes.append(DATA_SCOPE)
+
+        if self._admin:
+            scopes.append(ADMIN_SCOPE)
+
+        self._credentials = google.auth.credentials.with_scopes_if_required(
+            self._credentials, scopes)
+
     def copy(self):
         """Make a copy of this client.
 

spanner/google/cloud/spanner/client.py

@@ -35,8 +35,7 @@
 # pylint: enable=line-too-long
 
 from google.cloud._http import DEFAULT_USER_AGENT
-from google.cloud.client import _ClientFactoryMixin
-from google.cloud.client import _ClientProjectMixin
+from google.cloud.client import ClientWithProject
 from google.cloud.iterator import GAXIterator
 from google.cloud.spanner import __version__
 from google.cloud.spanner._helpers import _options_with_prefix
@@ -73,13 +72,13 @@ def from_pb(cls, config_pb):
         return cls(config_pb.name, config_pb.display_name)
 
 
-class Client(_ClientFactoryMixin, _ClientProjectMixin):
+class Client(ClientWithProject):
     """Client for interacting with Cloud Spanner API.
 
     .. note::
 
         Since the Cloud Spanner API requires the gRPC transport, no
-        ``http`` argument is accepted by this class.
+        ``_http`` argument is accepted by this class.
 
     :type project: :class:`str` or :func:`unicode <unicode>`
     :param project: (Optional) The ID of the project which owns the
@@ -104,21 +103,16 @@ class Client(_ClientFactoryMixin, _ClientProjectMixin):
     _database_admin_api = None
     _SET_PROJECT = True  # Used by from_service_account_json()
 
+    SCOPE = (SPANNER_ADMIN_SCOPE,)
+    """The scopes required for Google Cloud Spanner."""
+
     def __init__(self, project=None, credentials=None,
                  user_agent=DEFAULT_USER_AGENT):
-
-        _ClientProjectMixin.__init__(self, project=project)
-        if credentials is None:
-            credentials, _ = google.auth.default()
-
-        scopes = [
-            SPANNER_ADMIN_SCOPE,
-        ]
-
-        credentials = google.auth.credentials.with_scopes_if_required(
-            credentials, scopes)
-
-        self._credentials = credentials
+        # NOTE: This API has no use for the _http argument, but sending it
+        #       will have no impact since the _http() @property only lazily
+        #       creates a working HTTP object.
+        super(Client, self).__init__(
+            project=project, credentials=credentials, _http=None)
         self.user_agent = user_agent
 
     @property